HARTFORD, Conn. — With a new poll showing the race tightening between Democratic Sen. Joe Lieberman and his anti-war opponent, both sides made their final pitches to voters in the nation’s most closely watched primary election.

Lieberman planned to vote in his hometown of New Haven Tuesday morning and make six stops across the state before settling in at a Hartford hotel after polls close at 8 p.m.

Challenger Ned Lamont, a millionaire owner of a cable television company, held a slight lead of 51 percent to 45 percent over Lieberman among likely Democratic voters, according to a Quinnipiac University poll released Monday.

The telephone poll of 784 likely Democratic primary voters, conducted from July 31 to Aug. 6, has a sampling error margin of plus or minus 3.5 percentage points.

The race tightened in recent days, with Lamont’s lead cut from 13 points.

Primaries are also being held Tuesday in Colorado, Missouri, Michigan and Georgia. In Georgia, Rep. Cynthia McKinney, who made headlines this year for a scuffle with a U.S. Capitol Police officer, faced a runoff for her district’s Democratic nomination.

If defeated, Lieberman would be only the fourth incumbent senator since 1980 to lose a primary election.

Lieberman stays confidentSome Democrats object to the three-term senator and 2000 vice presidential candidate’s support for the Iraq war, saying he is too close to Republicans and President Bush. He has said he will run as an independent in the fall if defeated in the primary, though some backers would pressure him not to.

Lieberman said he believes voters are coming back to him.

“I feel they were flirting with the other guy for a while, wanting to send me a message,” he said Monday during a stop at a restaurant in Hartford. “I got their message. I think they want to send me back to Washington to continue working with them, fighting for them, and delivering for Connecticut.”

Lieberman acknowledged he was still behind. “I’m not kidding myself. But the momentum is our direction. I just hope and pray for a big turnout,” he said.

Quinnipiac Poll Director Douglas Schwartz said people may be having second thoughts about Lamont, whose only political experience is two years as a Greenwich selectman and six years on the town’s Board of Estimate and Taxation.

Many of Lamont’s supporters see the race as a chance to assume a bigger role in the Democratic party.

“People want change and people like what they hear from Ned,” said Liz Dupont-Diehl, Lamont’s campaign spokeswoman.

Should he lose Tuesday, supporters would have until Wednesday afternoon to submit petitions to put Lieberman’s name on the ballot as an independent.

Georgia representative fights criticsMcKinney, meanwhile, is trying to counter her opponent’s charge that the six-term congresswoman is “the candidate of polarization and divisiveness.”

McKinney, the state’s first black woman in Congress, once claimed the Bush administration had advance knowledge of the Sept. 11, 2001, terror attacks. In March, she struck a Capitol Police officer who did not recognize her and tried to stop McKinney from entering a House office building.

A grand jury in Washington declined to indict her, but she was forced to apologize in the full House. She drew less than 50 percent of the vote in last month’s primary and faces off against Hank Johnson, the black former commissioner of DeKalb County, which encompasses much of Atlanta.

In a radio ad, McKinney acknowledges that she’s “not perfect. But I’ve worked hard, told you the truth and I’m not afraid to speak truth to power,” she said.

In other primaries Tuesday:

In Colorado’s heavily conservative 5th District, voters will choose among six GOP candidates to succeed retiring Republican Rep. Joel Hefley, a 10-year veteran. The winner will face Democratic Air Force veteran Jay Fawcett. In another race, three Democrats are competing to replace U.S. Rep. Bob Beauprez, the Republican nominee for governor.

In Michigan, Republican Rep. Joe Schwarz faces a serious challenge from former state lawmaker Tim Walberg. Schwarz, a moderate Republican, is backed by President Bush, Arizona Sen. John McCain and the National Rifle Association. But the race has been dominated by a struggle over GOP principles. Outside groups have spent more than $1 million on the race.

Missouri Republican Sen. Jim Talent and Democratic challenger Claire McCaskill, the state auditor, are expected to win their party’s primaries. Voters will also decide whether to renew a 22-year-old sales tax to fund state parks and other conservation initiatives.